Previously, many granular products and some liquids have been shipped and stored in large bulk bags which may contain as much as a ton or more of material. Some of these bulk bags are flexible and when empty can be folded to a generally flat condition. One such flexible bag is disclosed and claimed in U.S. Pat. No. 4,790,029.
These flexible bags have generally rectangular ends interconnected by generally rectangular side walls and when filled can be stacked one on top of another. For some applications, preferably the bags are made of a woven fabric, and for other applications, a plastic material. For some applications, and particularly for storing liquids, a bag of a water impervious plastic material is received in and reinforced and protected by a bag of a woven fabric. Usually, these bags have a spout in one or both ends for filling and emptying the bags.
U.S. Pat. No. 4,362,199 discloses a bulk bag of woven fabric with lift straps attached to selected reinforced areas of the fabric. Each area is reinforced by a pluralilty of warp yarns of a higher tensile strength than the warp and weft yarns of the base fabric. The reinforced areas have a variety of spacings and configurations.